Oil circuit breaker



June 23, 1925.

A. J. BOWIE OIL CIRCUIT BREAKER Filed Dec. 5, 1921 2 Sheets-Sheet l INVENTOR. WJMM June 23, 1925. 1.543.495

- A, J. BOWIE OIL CIRCUIT BREAKER Filed Dec. 5, 1921 2 Shouts-Shoot 2 H INVENTOR.

Patented June 23, 1925.

- UNITED STATES 1,543,435 PATENT OFFICE.

AUGUSTUS JESSE BOWIE, OF SAN FRANCISCO, CALIFORNIA.

OIL CIRCUIT BREAKER.

, .Application filed December 5, 1921. Serial No. 520,095.

To all whom it mag/concern: A Be it known that I, AUGUSTUS Jnssn Bowls, a citizen of the, United States, residing at San Francisco, county of San Francisco, State of California, have invented certain new and useful Improvements in Oil Circuit Breakers; and I' do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which they appertainto make and use the same.

It is the object of this invention to provide improvements in oil circuit breakers.

The invention has reference to the design of the circuit breaker proper for operation under oil, and to the mechanism for tripping and opening the same. The underlymg principles governing the successful operation of an oil circuit breaker, are:

First: That there must be a sufficient head of oil over the break to extinguish the are promptly, and I, p I

Second: That the motion of the break, particularly when the blade leaves the follower contact, must be rapid.

In my breaker the arc is interru )ted in a horizontal plane, thus roviding t e maxi mum possi le depth oil over the break without increasing the depth of the tank. The arrangement is such that the'inertia of the moving parts is reduced to a'minimum, and the initial art of the break is accom-- plished very quickly thru a combination of mechanisms outlined hereafter. y

Fig. 1*1s a plan view in section of the breaker along line (A. A) of Fig. 2.

Fig. 2-is a sectional view of the breaker along the line (B. B.) of Fig. 1, one of the two main insulators entering the tank being shown in projection. I

Fig. 3--is. a plan view of the trip mechanism.

Fig. 4-is an elevation of the same.

Fig. 5is a plan view showing a general arrangement of the 3 poles of a 3 pole breaker, together with the trip mechanism. Fig. 6-is a diagrammatic plan of the mechanism of the breaker in the tank, showing the position of the blades when open and closed.

Fig. 7 is a plan view of the breaker with the blades in open position, corresponding to Fig. 1, which is in closed osition.

(l) is the casing for 1 1 ing the oil of the breaker, (2) is the top of the breaker, (3, are the main, insulators carrying the entering and outgoing leads from the breaker; (4, 4) are conductors for carrying the leads thru the centers of insulators (3, 3) to the switch terminals in the lower part of the case. (5, 5) are flanges cemented to insulators (3, 3) ada ted to secure them by pieces (53, 53) to ti IS a cast iron support attached to top (2), (7) is a crank, (8) is a crank pin, a connecting rod, (10) a shaft fast to crank 7, (11) is a coupling secured to shaft 10, and also to rod (12) which may be made of wood or other insulating material, (13) is an insulating tube rigidly suported in cap 6, provided with cap 14, at its lower end, (15) is a crank attached to the lower end of rod 12, provided with two clevis type ends in which the link ends (16) are pivoted by pins 18. Connected thereto are adjustable link ends (17, 17), which connect to hinged blades (20, 20) thru pins (19, 19). (21, 21) are main clips, preferably made of wedge type mounted in turn on the supports (23, 23) which are secured to supporting flanges (24, 24) secured in turn to the lower end of insulators (3, 3) and electrically connected to conductors (4, 4). (22, 22) are follower contacts, which as shown, make a surface contact wlth the ends of blades 20, 20, so that the blade has to travel to the end of said contacts before the arc starts to break. These contacts may be either made in the form of parallel plates or may be made with a spring follower which will contact with the inner edge of the end of the bladea type which is common with circuit breakers. (26, 26) are projections from cap 14, provided with slots or corresponding supportlng and current carrying attachments for blades 20, 20, which as shown are secured thru pins (25, The type illustrated is sim lar to the usual type of binge end for a swltch blade.

In Figs. 3, 4 and 5; 27 is the trip shaft supported in bearing 29, attached to supporting base 28. (30) 1s a stop for limit ng the motion of the mechanism for opening the breaker which is made approximately 180; (31) is a crank rigidly attached to shaft 27 carrying an arm 32, on the outer end of which is a forked lever (36) provided with a pinioned roller 37, operatmg on pin 38; 36 is pivoted by pin 39 on arm 32. .is a crank loosely mounted on shaft 27 and carrying a bossed portlon in which anges in cover 2, for supporting the insulators thereon. (6)

the pin Si, is secured; it is also provided with an arm, The connecting links 0, 9 connect the different poles of the breaker together, the type shown herein having each pole in a separate casing. In Figs. st and 5 the outer ends of link 9 are attached to pin 23 i, and the motion of the shaft 2'7, thru approximately 180 operates the difl'erent poles of the breaker simultaneously. The roller 37, engages the outer end of arm 33, and is held in engagement by the light spring it), one end of: which is attached to arm 32, and the other end to piece 36.

is the stop on arm limiting the motion of the piece 36, when disengaged from arm 33. Arm 33, however, as shown is provided with a bossed portion at the end which limits the position of roller 37, when in engagement therewith. (a0) is a spring adapted to open the breaker, pressing against collar l8, the inner end being held by piece t7, which has a slotted hole for red 9 and is attached to base 28; (ll) is the outer end of piece 36; is a limit stop attached to the base 28 adapted to limit the motion of crank 31 on the closing of the breaker. is a latch mounted in piece all and pressed forward as shown by spring mounted on lug l6, secured on base 28.

6 shows in principle the diagrammatic operation of the mechanism within the breaker tank, the full line showing the breaker closed and the dotted line showing the breaker in open position.

One important feature of this breaker is the ;tactthat when in open position the blades conform very closely to the limit of the supporting mechanism, thus keeping the width of the tank within reasonable limits.

A study of the ope 'ating mechanism as shown indicates the following very important features:

In the closed position the crank 15, together with links connecting to the blades form a toggle connection thus giving a maximum pressure to hold the blades in the contact clips with the minimum strain on the operating mechanism. The piece 11, is flexibly connected to shait 10, and the lower end of rod 12, rigidly connected to the hub of crank 15, playsloosely in cap It. This allows equalization of the strains on the two blades by allowing a small motion at the lower end, it the strains-tend to be unequal. This equalizer is obviously of considerable importance. It is evident that the.

cap 14, is subject to very little strain in the switch operation since the major portions of the strains are self-contained and pass directly thru the metal from one side to the other, thus minimizing the mechanical strains otloperation.

The initial movement of the breaker in opening blade 20, is slow,due to the toggle action. However, a study of themeehanism as outlined shows that by the time the blade has reached the outer end of the clip 22, at which point the contact is finally broken, this toggle is entirely done away with and the motion is extremely rapid for a small angle of motion of the operating rod 12. This very desirable result secures a maximum speed just where it is required. Most oi? the inertia of the moving parts lies in the blades 20, 20, which are short and light, and hence allow great rapidity of action. These blades may, if desired, be provided with limit stops striking against each other, which tend to prevent jar when the breaker is opened, thus pieces 51, 51, with bun'ipers 52, 52, form opposing limits for striking together when the blades are open. Horizontal break switches of ditl'erent types have been used before, but the prin ciples involved herein, the avoidance of inertia and the sinnalicity of o ')eration make my switch particularly desirable.

lVithrelcrence to the operating mechanism, Figs. 3, 4:, and 5 show the breaker in the closed position. Spring l0 which presses thru the rod 9, 011 pin 34;, is slightly oll' center of the full closed position and tends to turn crank 35, which however, is held from turning by roller 37, attached thru pins 38, 39 and piece 36 to arm 32 and crank 31. Crank 31 is held from opening by latch 43. The automatic trip mechanism for opening the breaker, (not shown herein, as there is nothing new involved in this mechanism in my breaker) strikes lightly against ll, in a downward direction. A comparatively small, pressure is required to make roller 3'7 slip off the end of arm 3 since not onlyiis the torque of spring it), about shaft 24 made comparatively llght,

but the roller arrangement is such as to cut down to a minimum the power required for operation.

lVhen the arm 32- is released from roller 3?, spring 40 will cause it to open and travel thru nearly 180 the outer end of the stroke i being limited by arm 33 impinging on stop 30. 'lhismotion.thru1S0 is very desirable, since at the open end of the stroke the crank going thru dead center has taken are of the motion oil all the moving parts of the breaker, except the inertia of arm 33, and minor other parts so that the hammer blow .on the stop is quite light. \Vhile it might seem at first glance, objectionable to have a travel ot 180 on the ground that it would make too slow an initial break of the breaker, yet a study of the mechanism as laid out, shows that this 18 not the case, and that the connecting rod 9, will have attained nearlyyits maximum speed at the moment the breaker blade actually leaves the clips. The small lever arm of rod 9 in the closed posit-ion around the shaft 27, results in comparatively light pressure against the roller 37, minimizing the power required for the trip of the breaker. To release the breaker manually the details of the trip are not shown, as the do not form a part of the patent, but this can be readily accomplished by the manual trip first pressing against lever 41 and then opening latch 43, allowing the breaker to open of itself and the operating handle to be opened either by a spring or by other means.

What I claim is:

1. In an oil circuit breaker a pair of electrically connected blades hinged on different axes for opening and closing the circuit, adapted to be substantially parallel throughout their travel, said blades operating in opposite directions.

In an oil circuit breaker a pair of electrically connected'blades, adapted for opening and closing the circuit, a supporting member in which said blades are rotatably mounted, the outer end of each blade being in proximity to the supporting end of the other blade when the breaker is open.

3. In an oil circuit breaker, a pair of electrically connected blades adapted to open and close the circuit, a central supporting member in which said blades are separately hinged on different axes, and means for opening and closing said breaker thru the operating of said blades which are adapted to remain substantially parallel at all points of the stroke.

4. In an oil circuit breaker a pair of electrically connected blades adapted to open and close the circuit by rotation in the same direction, a supporting structure on which the ends of said blades are separately mounted and a central rotating member adapted to operate said blades.

5. In an oil circuit breaker a pair of electrically connected blades adapted to open and close the circuit by rotation in the same direction, a supporting structure on which said blades are separately mounted, links connecting with said blades, and a central rotating member adapted to operate said blades thru said links.

6. In an oil circuit breaker a pair of blades adapted to open and close the circuit, an insulated supporting structure in which said blades are separately mounted, links connecting with said blades and a central rotating member adapted to operate said blades thru said links, said blades being substantially parallel at all points of the stroke.

7. In an oil circuit breaker, a pair of pivoted electrically connected blades adapted to operate said breaker by rotation in the same direction, a pair of pivots, supports for said pivots, and a central rotating shaft adapted said blades, the mechanism being adapted to open and close the breaker.

9. In an oil circuit breaker a pair of electrically connected blades, supports for same in which said blades are separately pivoted, a central operating shaft provided with two cranks, a pair of links connecting said cranks to said blades, the links and cranks constituting substantially a toggle mechanism when the breaker is closed.

10. In an oil circuit breaker, a pair of electrically connected blades for opening and closing the circuit, a central supporting member on which said blades are pivotally mounted, in combination with a central operating member adapted to operate said blades, said supporting member and said operating member being co-axial.

11. In an oil circuit breaker a pair of electrically connected blades for opening and closing the circuit, a tubular supporting member on which said blades are pivotally mounted, in combination with an operating member adapted to operate said blades, said tubular member and said operating member being co-axial.

12. In an oil circuit breaker a pair of blades for opening and closing the circuit, a tubular supporting member on which said blades are pivotally mounted, in combination with an operating member operating within said tubular member, said operating member being adapted to operate said blades.

13. In an oil circuit breaker a pair of blades for opening and closing the circuit in combination with bumpers on said blades, said bumpers being adapted to impinge on each other when the breaker is opened, thereby limiting the motion and taking care of the inertia of said blades.

14. In an oil circuit breaker, a pair of separately pivoted blades adapted to open and close the circuit, a rotating shaft adapted to operate said blades, a loose fitting bearing for said shaft adapted to allow equalization of the pressures of closure on said blades.

In testimony whereof, I affix my signature, in the presence of two witnesses.

AUGUSTUS JESSE BOVVIE. Witnesses:

GERTRUDE F. REED, CHARLES H. WATSON. 

